Serial study of factors influencing changes in cardiac output during human pregnancy

Abstract

Serial hemodynamic measurements were performed in 13 women on two occasions before conception and then at monthly intervals throughout pregnancy. Cardiac output (CO) was measured by Doppler and cross-sectional echocardiography at the aortic, pulmonary, and mitral valves. Cardiac chamber size and ventricular function were investigated by M-mode echocardiography. CO increased from a mean of 4.88 l/min before the conception to a maximum of 7.21 l/min at 32 wk, the increase being significant by 5 wk after the last menstrual period. Heart rate and left ventricular performance increased during the first trimester. Heart rate increased further during the second trimester, during which left atrial and left ventricular end-diastolic dimensions increased, suggesting an increase in venous return. Derived values of total peripheral vascular resistance fell during the first 20 wk. These changes were associated with a progressive increase in valve orifice area and left ventricular wall thickness during pregnancy.

Mitral valve leaflet remodelling during pregnancy: insights into cell-mediated recovery of tissue homeostasis

“…This contrasts with pregnancy-induced LV remodelling, which has been shown to be significant just one month after conception [10]. In our results of fibre splay and recruitment stretch, it is apparent that the trend lines for the actual results begin deviating from that which is predicted by the bulk dimensional changes at a gestation time of about 80 days (figure 9).…”

“…This is because pregnancy induces a wide array of cardiac changes, as the presence of the fetalplacental unit places additional demands on the maternal heart. Among these effects, some of the most notable in humans include 50% increases in cardiac output and LV mass, a 40% increase in blood volume, a 30% increase in stroke volume, a 20% increase in end-diastolic LV volume and a 12% increase in MV orifice area [9][10][11]. At the organ level, the MV is connected to the LV through the chordae tendineae and papillary muscles (PMs) as well as the annulus, making its mechanical behaviour tightly coupled to that of the LV.…”

Comparison of subfoveal choroidal thickness in healthy pregnancy and pre-eclampsia

“…28 In addition, gestational age should be considered in studies of pregnant women because systemic and ocular changes persist until the end of the pregnancy. [28][29][30][31] In this study and Takahashi et al, the target subjects were limited to the last trimester, whereas Sayin et al included subjects in both the second and third trimesters, which may have caused the difference. Moreover, as mentioned previously, endothelial cell dysfunction and hyperpermeability are major causes of multi-organ failure in pre-eclampsia.…”

The 2010 Canadian Cardiovascular Society guidelines for the diagnosis and management of heart failure update: Heart failure in ethnic minority populations, heart failure and pregnancy, disease management, and quality improvement/assurance programs

“…During the peripartum period, further changes are noted as well (65)(66)(67)(68). Maternal position can have a significant effect on cardiac output.…”